The "rules" of inheritance in England, France and especially Germany based on local law and were not all the same durnig the middle ages. Actually the nobles in Europe used several different kind of "sytems" for chosing their King/Emperor, depending on location and tradition. Moreover, time also plays a role: While during the Middle Ages the Kings of Western Europe (and their Inheritance) became more and more stronger, we observe the opposite in Germany.
Creating a game mechanic simulating this would certainly be tough, although it would be really nice to have.
Creating a game mechanic simulating this would certainly be tough, although it would be really nice to have.